Three-dimensional monitors capable of displaying stereoscopic images are known. Such three-dimensional monitors either require special glasses for enabling a viewer to view stereoscopic images or enable viewing of stereoscopic images with the unaided eye without having to use special glasses. Besides, an information processing device is known that includes an input device for enabling operations of stereoscopic images displayed in a three-dimensional monitor. As far as the input methods using an input device are concerned, a two-dimensional operation input method is known in which a mouse or a touch-sensitive panel is used and is three-dimensional operation input method is known in which a pen-type input device is used.
However, in the conventional technology, when a display area for displaying two-dimensional images and a display area for displaying stereoscopic images are present in the same screen, it is difficult to intuitively operate the stereoscopic images displayed on the screen.